--- /dev/null
+#include <ccan/tally/tally.c>
+#include <ccan/tap/tap.h>
+
+int main(void)
+{
+ int i;
+ struct tally *tally = tally_new(100);
+ ssize_t min, max, mode;
+ size_t err;
+
+ max = (ssize_t)~(1ULL << (sizeof(max)*CHAR_BIT - 1));
+ min = (ssize_t)(1ULL << (sizeof(max)*CHAR_BIT - 1));
+
+ plan_tests(100 + 50 + 100 + 100 + 10);
+ /* Simple mode test: should always be around 0 (we add that twice). */
+ for (i = 0; i < 100; i++) {
+ tally_add(tally, i);
+ tally_add(tally, -i);
+ mode = tally_approx_mode(tally, &err);
+ if (i < 50)
+ ok1(err == 0);
+ ok1(mode - (ssize_t)err <= 0 && mode + (ssize_t)err >= 0);
+ }
+
+ /* Works for big values too... */
+ for (i = 0; i < 100; i++) {
+ tally_add(tally, max - i);
+ tally_add(tally, min + 1 + i);
+ mode = tally_approx_mode(tally, &err);
+ ok1(mode - (ssize_t)err <= 0 && mode + (ssize_t)err >= 0);
+ }
+ free(tally);
+
+ tally = tally_new(10);
+ tally_add(tally, 0);
+ for (i = 0; i < 100; i++) {
+ tally_add(tally, i);
+ mode = tally_approx_mode(tally, &err);
+ if (i < 10)
+ ok1(err == 0);
+ ok1(mode - (ssize_t)err <= 0 && mode + (ssize_t)err >= 0);
+ }
+
+ return exit_status();
+}